How Jeff Han Created the World-Record 82-Inch Multitouch LCD

If you've seen the huge touchscreens that CNN newspeople gleefully use on their broadcasts, then you've seen the work of Jeff Han. He won a 2007 Popular Mechanics Breakthrough Award for his supersize multitouch screen, which measured 103 inches. But Han wanted a version that was flat, like the iPhone or an LCD TV. This year he reached that goal: His company, Perceptive Pixel, put out a 27-inch multitouch interface in May, followed by an 82-inch LCD version in August. We caught up with him to ask about the challenges of creating a screen this size, and the future of multitouch technology.

Your screens are already used by companies around the world, including CNN. Why redesign a successful product?

The company had found a breakthrough technology and it served us well, but the problem was, the technology didn't really scale well down to LCDs. The screens required a projector behind them a few feet deep. While it doesn't really matter from a usability point of view, if you walk to the wall and look behind it, you'd see a pretty big setup. It just limited our adoption.

But multitouch was just getting started. When we started the company, we had to explain to everybody what multitouch was. People are now used to these iPhone and iPad-like devices, and they expect the same kind of feeling using the larger screens. A new standard was coming out, and frankly, that was the iPhone. So we had to ask ourselves, "Hey, can we use the technology to actually make the tech flatget rid of the projector?"

Companies have had a hard time scaling up projective-capacitor screensthe technology that the iPhone and iPad use. Why?

Well, it turns out that the core technology is very difficult to scale up. To be honest, we were searching for a way to do this for years because I really wanted to get rid of that projector. I wanted it flat. LCDs are flat, TVs and mobile devices are flat. How can we make our multitouch flat? Making projective-capacitor sensors, or capacitive sensors at all, is actually pretty remarkable. You're trying to measure really tiny capacitance changes, femtoFaradsyou know, that's a millionth of a nanoin the environment at the screen. I actually asked a lot of companies who make these kinds of things for the mobile devices if they could make us a bigger one. They all said no. I just never accepted that. It turns out, we discovered how we can do it, and that was very cool. In May, when we launched our 27-inch versionby far the largest pro-cap device on the marketit blew a lot of people away. Nobody thought it could be done. And we did it, without compromise.

You say size isnt the only new feature for this product. What else have you done here?

The biggest difference is that we've optically bonded the sensor to the display. Most companies take an LCD and sort of slap their touch sensor on top with a space in between. The reason for the space is, if you put them right up against one another, they start scratching each other. And, as it turns out, the display itselfthe liquid crystaland the electronics behind the display cause a lot of noise, which interferes with the touch sensor.

Once you go larger scale, you have to make the glass thicker to stop flexing. For other companies, their answer was to push the sensor glass further away from the display. That distance between the sensor glass and the display is called parallax. The problem with that is, yes, it works, but it doesn't work for the user. The user tries to touch the screen, but this barrier keeps it several millimeters away. It doesn't feel rightyou're not really touching the glass, you're touching something in front of it. And it's not just a cosmetic concern. It actually causes you to miss buttons and you can't be precise in professional applications. Our closest comparable product has a 20-mm parallax for a 20-inch display. Everyone complains about it.

So how did you overcome the parallax issue?

We specifically designed the controllerwhat the technology is called in the industryto allow us to overcome the problems. If we can overcome the noise, we can actually put the sensor right on the LCD itself. I can't reveal too many of our secrets, but we've developed a great algorithm that works mostly in the digital domain, using digital-signal processing techniques that extract out that really weak signal. Our technology is doing some pretty sophisticated digital-signal processing techniques that can track it out. And this allows us to put the sensor wherever we want.

Other than solving the parallax problem, there are a lot of incremental benefits that come along with optical bonding. The contrast is so rich and deep and the colors really pop. It's like the difference between looking at a TV through a windowpane and looking at a piece of jewelry in front of you.

With iPhones and iPads everywhere, what place does such a large multitouch screen have in the marketplace?

When we first introduced multitouch on these large walls, everyone started making these small multitouch devices. So why gather around a display when we all have personal displays? That is actually something I didn't anticipate. I don't think very many people anticipated the rise of mobile. But walls, tabletops and larger surfaces in general allow us to start breaking down the one-to-one ratio that is traditional computing. You start having displays that are shared by multiple people. So, while a lot of the smaller devices are collaborative and great for accessing information at your fingertips, what large displays do is allow you to collaborate [on the same screen], the same way a notebook lets you take notes for yourself and a white board lets people work together. This company isn't about multitouchit's about multi-user. It's about, "How do we actually get collaboration going between multiple users?"

The 27-inch version came out in May. What has the response been like?

The response has been unbelievable. Frankly, we can't make them fast enough. We launched the 27-inch, still targeting our traditional market, government and intelligence workers. But one of the most exciting things about the device, which we really saw at the big computer-graphics and interactive-techniques conference SIGGRAPH, was how this desktop-size device can actually impact the content-creation community: publishing, the arts, film. Those are such fantastic communities, and they've been so responsive to the company over all these years. But I felt like we didn't have a product that was really good for themuntil the 27-incher came out.

Whats the next big thing for Perceptive Pixel?

We believe the next big thing is the stylusbeing able to work with a pen in your hand. As much as I'll say multitouch is great, multitouch also sucks, and I'll be the first to admit it. We don't advocate that multitouch is great for everything. People say, Oh, so you must hate the keyboard and mouse! and I'm like, No, not at all. I love the keyboard and mouse. I love the feeling of tactile keys. It's great for a lot of things.

We're constantly looking for other technologies. And it turns out that there's a pretty obvious answer, and that's the stylus. At SIGGRAPH, we revealed to the world that we were developing our own projected-capacitive multitouch controller not just for multitouch, but for stylus too. You can imagine the creativesartists, animatorswho were all drooling. All these major studios that we've been talking toDreamWorks, Disney, Pixarthey were like, Wow, this is good. That's actually why the creative community was so excited now with this smaller product. Not only is it personal, it has a pen.